Well, it took them long enough. Apple has finally acknowledged the existence of the MAC Defender trojan, and has offered removal instructions. The company has also promised a security update to Mac OS X that will block MAC Defender and its variants from working. All this information was published in the form of a support document on Apple's website. Update: Well, that was fast. A new variant of the trojan, called Mac Guard, has been discovered. Unlike previous variants, this one does not require users to enter their administrative password.